In a current wireless communication environment, the emergence and proliferation of various devices such as Machine-to-Machine (M2M) devices conducting M2M communication, smart phones requiring large-data transmission, and tablet computers is a driving force behind a very rapid increase in the amount of data required for a network of a wireless communication system. To meet the requirement of a larger amount of data, carrier aggregation and cognitive radio have been developed to efficiently use more frequency bands, and multi-antenna technology and multi-base station cooperation technology have been developed to increase a data capacity in a limited frequency. The wireless communication environment is evolving toward more densely populated nodes accessible to users. Such a system having densely populated nodes may provide higher system performance through cooperation between nodes. In this scheme, each node conducts cooperative communication through a plurality of nodes operating as Base Stations (BSs), Advanced BSs (ABSs), Node Bs, evolved Node Bs (eNBs or eNode Bs), Access Points (APs), antennas, antenna groups, Remote Radio Heads (RRHs), or Remote Radio Units (RRUs).
Further, if one controller manages transmission and reception of all nodes and thus individual nodes act as antenna groups of an eNB, this system may be regarded as a Distributed Multi-Node System (DMNS). The individual nodes may be allocated separate Node Identifiers (IDs) or operate as some antennas of a cell without Node IDs.
If the nodes of a DMNS have different cell IDs, this system may be considered to be a multi-cell system (e.g. including a macro cell, a femto cell, and a pico cell). If the multiple cells formed by the respective nodes are overlaid according to their coverage, this network is referred to as a multi-tier network.
Various types of BSs may be used as nodes irrespective of their appellations. That is, a BS, a Node B, an eNB, a Picocell eNB (PeNB), a Home eNB (HeNB), an RRH, an RRU, a relay, a repeater, etc. may act as a node. At least one antenna is installed in one node. The antenna may be any of a physical antenna, an antenna port, a virtual antenna, and an antenna group. A node may also be referred to as a point.
Although a node typically refers to an antenna group spaced by a predetermined distance or more, the node may mean an arbitrary antenna group irrespective of the distance. For example, an eNB may control a node having H-pol antennas and a node having V-pol antennas. In the present disclosure, the term antenna may be replaced with the terms physical antenna, antenna port, virtual antenna, antenna group, etc.